Repercussion, Screaming Nemesis, and With Great Power...

Prerequisites

• Repercussion on the battlefield
• Screaming Nemesis on the battlefield
• With Great Power
• on the battlefield

Steps

1. Deal damage to Screaming Nemesis
2. Screaming Nemesis and Repercussion trigger
3. Resolve the Screaming Nemesis trigger, dealing damage to an applicable target
4. Resolve the Repercussion trigger, dealing damage to Screaming Nemesis instead of you due to With Great Power
5. Repeat from step 2

Results

• Infinite damage